<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>数组的一些方法</title>
</head>
<body>
  <script>
    // charAt charCodeAt concat endsWith startsWith includes indexOf match matchAll normalize padStart padEnd repeat replace
    // search slice split substring toLowerCase toUpperCase trim valueOf toString
    const arr = '123';

    // valueOf的结果与toString是一样的

  </script>
</body>
</html>